System and method for monitoring end nodes using ethernet connectivity fault management (CFM) in an access network

ABSTRACT

A system and method for monitoring end nodes using Ethernet Connectivity Fault Management (CFM) in an access network. In one embodiment, a broadband access server (BRAS) is operable to generate an Ethernet CFM frame that includes a query message with respect to a particular end node. An interworking function (IWF) entity associated with an access node that services the particular end node is operable to interpret the Ethernet CFM frame and construct a corresponding query message in a native protocol compatible with the particular end node. Upon receiving a reply message from the particular end node, the IWF entity constructs a suitable reply Ethernet CFM frame for transmission to the BRAS, wherein the reply Ethernet CFM frame includes a response corresponding to the reply message from the end node.

PRIORITY UNDER 35 U.S.C. §119(e) & 37 C.F.R. §1.78

This nonprovisional application claims priority based upon the followingprior United States provisional patent application(s): (i) “INTERWORKINGBETWEEN METRO ETHERNET AND ACCESS OAM,” Application No. 60/643,945,filed Jan. 14, 2005, in the name(s) of: Kamakshi Sridhar, Sven Ooghe,Maarten Petrus Joseph Vissers and Atiya Suhail; and (ii) “BROADBANDACCESS END-TO-END CONNECTIVITY TESTING WITH CFM OAM IN THE ACCESSNETWORK,” Application No. 60/656,487, filed Feb. 25, 2005, in thename(s) of: Kamakshi Sridhar, Sven Ooghe, Maarten Petrus Joseph Vissersand Atiya Suhail; each of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention generally relates to access networks thatincorporate Ethernet aggregation. More particularly, and not by way ofany limitation, the present invention is directed to a system and methodfor monitoring end nodes using Ethernet Connectivity Fault Management(CFM) functionality.

2. Description of Related Art

Current first/last mile access network solutions have significantshortcomings from subscribers' perspective, ranging from performancebottlenecks, fixed bandwidth provisioning, limited scalability, lack offlexibility and provisioning complexity to end-to-end quality of service(QoS) issues and a high cost structure. Application of robust, simpleEthernet technology in the first mile promises to revolutionize theaccess network as it did in the arena of enterprise networks where itstarted out as a local area network (LAN) transport technology that isused to communicate between computers and networks. As an accesstechnology, Ethernet offers three significant advantages over legacyfirst mile technologies: (i) future-proof transport for data, video andvoice applications; (ii) cost-effective infrastructure for dataservices; and (iii) simple, globally accepted standard that will ensureinteroperability.

In order to adapt the Ethernet technology in a carrier-grade serviceenvironment, various standards are being developed that aim to provideadvanced Operations, Administration and Management (OAM) capabilities(also referred to as Ethernet Connectivity and Fault Management orEthernet CFM) across the entire network from one end to the other end.Since the end-to-end service network environment is typically comprisedof a patchwork of diverse component networks (e.g., metro accessnetworks and core networks using a variety of technologies) that maybelong to different organizations, network operators and serviceproviders, the Ethernet CFM plane is envisioned as a hierarchicallylayered domain space wherein specific CFM domains (or, synonymously OAMdomains) are defined corresponding to the constituent networkinfrastructure and provisioning. In particular, two standards, IEEE802.1ag and ITU-T draft Recommendation Y.17ethoam, incorporated byreference herein, that are specifically concerned with end-to-endEthernet CFM define a customer-level domain at the highest level ofhierarchy, which comprises one or more provider domains (occupying anintermediate level), each of which in turn includes one or more operatordomains disposed at a lower hierarchical level. By way ofstandardization, the CFM domain space may be partitioned into a numberof levels, e.g., 8 levels, each domain corresponding to a particularlevel, wherein a domain is defined in terms of what are referred to asflow points. In the context of the IEEE 802 specification suite, theflow points are new entities contained in the Media Access Control (MAC)“interfaces” and “ports” as defined in related standards documentation.A port can implement multiple flow points of different types. The flowpoints are generally referred to as ETH flow points and bound either a“Maintenance End Point” or MEP compound function or a “MaintenanceIntermediate Point” or MIP compound function. Typically, the MEPcompound functions are disposed at the edge of a CFM domain whereas theMIP compound functions are disposed inside a domain and remain visibleto the bounding MEP functions. A node may implement a MIP function, aMEP function, or both, depending on how the domains are configured.Accordingly, the terms “MEP node” and “MIP node” may be used to looselydefine a node functionality that implements a MEP compound function anda node functionality that implements a MIP compound function,respectively, although they may be defined on one single node. WhereasMEP “nodes” are used by system administrators to initiate and monitorCFM activity (by issuing appropriate CFM frames), MIP “nodes” passivelyreceive and respond to CFM flows initiated by MEP “nodes”.

A CFM domain having one or more MIP nodes may be bounded by a pluralityof MEP nodes. In order that CFM frame flows are appropriately filteredso that they are processed only by the intended domain's nodes, theMEP/MIP population of an Ethernet CFM network is configuredappropriately. For instance, in accordance with the current standards,an integer value may be provided to indicate a specific domain level ofan Ethernet CFM hierarchy.

Moreover, standards are also being specified to enhance service deliverytechnologies, which allow provisioning of Virtual LANs (VLANs) on top ofa Data Link Layer (i.e., Layer-2 or L2) Ethernet network for addingflexibility, scalability and security to the CFM network. VLANs may bedefined on different levels, e.g., customer-level, provider-level, etc.,and can include any number of non-intersecting CFM domains. Serviceframe fields preceded with a “C-”, e.g., C-VLAN ID, refers tocustomer-created fields. Likewise, service frame fields preceded with a“S-” (e.g., S-VLAN ID), refer to service provider-added fields. Byimplementing VLANs, an end-to-end Ethernet CFM network may bepartitioned into a number of service instances while preserving multiplesubscribers' C-VLANs, wherein the traffic in a given VLAN is invisibleto end hosts belonging to a different VLAN, thus reducing the broadcastdomain.

Although the Ethernet CFM architecture as currently being standardizedprovides an impressive framework for addressing end-to-end EthernetConnectivity and Fault Management at any level of the hierarchy, anumber of issues remain to be solved. Of particular concern is themonitoring of end nodes where access links that couple the end nodes(i.e., customer network sites) to a metro provider network may operatein a non-802.1ag environment, whereas the metro provider network maycomprise an 802.1ag-compliant network.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a monitoring methodoperable with an access network for testing, querying, or otherwisemonitoring end nodes using Ethernet CFM in the access network. Theaccess network includes at least one access node connected to one ormore end nodes and a broadband access server (BRAS) connected to aregional Ethernet network. In one embodiment, the method comprises:generating by the BRAS an Ethernet CFM frame directed to an access nodeassociated therewith, wherein the Ethernet CFM frame includes a querymessage with respect to a particular end node served by the access node;interpreting the Ethernet CFM frame by an interworking function (IWF)entity associated with the access node and constructing a correspondingquery message in a native protocol compatible with respect to theparticular end node; responsive to the corresponding query message fromthe access node, generating by the particular end node a reply messagein the same native protocol or a different native protocol directed tothe access node; interpreting the reply message by the IWF entity andconstructing a reply Ethernet CFM frame including a response thatcorresponds to the reply message from the end node; and transmitting thereply Ethernet CFM frame to the BRAS.

In another aspect, the present invention is directed to a monitoringsystem associated with an access network, wherein the access networkincludes at least one access node connected to one or more end nodes anda BRAS node connected to a regional Ethernet network. In one embodiment,the system comprises: means associated with the BRAS for generating anEthernet CFM frame directed to an access node associated therewith,wherein the Ethernet CFM frame includes a query message with respect toa particular end node served by the access node; IWF means associatedwith the access node for interpreting the Ethernet CFM frame andconstructing a corresponding query message in a native protocolcompatible with respect to the particular end node; means associatedwith the particular end node, operable responsive to the correspondingquery message from the access node, for generating a reply message inthe same native protocol or a different native protocol directed to theaccess node, wherein the IWF means operates to interpret the replymessage in the native protocol and constructs a reply Ethernet CFM frameincluding a response that corresponds to the reply message from the endnode, the reply Ethernet CFM frame for transmission to the BRAS.

In yet another aspect, the present invention is directed to a networkelement operable in an access network, comprising: a logic structureadapted to interpret an Ethernet CFM frame received from a BRAS nodedisposed in the access network, the Ethernet CFM frame including a querymessage with respect to an end node served by the network elementoperating as an access node; a logic structure adapted to construct acorresponding query message in a native protocol compatible with the endnode, the corresponding query message being based on the query messagein the Ethernet CFM frame; a logic structure adapted to interpret areply message provided by the end node responsive to the correspondingquery message, the reply message being compatible with the same nativeprotocol or a different native protocol; and a logic structure adaptedto construct a reply Ethernet CFM frame including a response thatcorresponds to the reply message received from the end node, the replyEthernet CFM message for transmission to the BRAS.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated into and form a part of thespecification to illustrate one or more presently preferred exemplaryembodiments of the present invention. Various advantages and features ofthe invention will be understood from the following Detailed Descriptiontaken in connection with the appended claims and with reference to theattached drawing figures in which:

FIG. 1 depicts an exemplary network arrangement including an accessportion with Ethernet aggregation wherein an embodiment of the presentpatent disclosure may be practiced;

FIG. 2 depicts an exemplary scheme according to one embodiment foreffectuating port testing with Ethernet CFM in the network arrangementshown in FIG. 1; and

FIGS. 3A and 3B depict exemplary Ethernet CFM frames operable foreffectuating port testing according to one embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference tovarious examples of how the invention can best be made and used. Likereference numerals are used throughout the description and several viewsof the drawings to indicate like or corresponding parts, wherein thevarious elements are not necessarily drawn to scale. Referring now tothe drawings, and more particularly to FIG. 1, depicted therein is anexemplary network arrangement 100 including an access portion 104 withEthernet aggregation wherein an embodiment of the present patentdisclosure may be practiced for monitoring an end node using EthernetCFM messaging. Preferably, the Ethernet CFM messaging is maintainedin-band with respect to the data transmission path in the accessnetwork. A regional or metro Ethernet network 102 including one or morerouters 116 and one or more Authentication, Authorization and Accounting(AAA) servers 118 is operably coupled to the access network portion 104.In a typical deployment, the infrastructure of the access network 104may include one or more access nodes 108 that may be aggregated via anEthernet switch 112 to a broadband access server (BRAS) node 114. Forpurposes of the present patent disclosure, the access network 104 may becomprised of any type of first/last mile access network technology ingeneral (e.g., Digital Subscriber Line (xDSL), Ethernet in First Mile(EFM), Asynchronous Transmission Mode (ATM), etc.), which may beimplemented using diverse physical transport media (such as wireless,wireline, all-optical, electro-optical, and the like). Accordingly, oneskilled in the art should recognize that the access networkinfrastructure may include appropriate access node elements (e.g., oneor more DSL Access Multiplexer or DSLAM elements) depending onparticular deployment, wherein the elements are suitably adapted forEthernet aggregation via other Ethernet-compatible elements such asEthernet switch 112 and BRAS 114.

Regardless of the type of access network technology, the access node 108is operable to serve one or more end nodes 106 generally located atcustomer premises. End nodes 106 may be comprised of differentequipment, e.g., DSL modems, network termination (NT) units, residentialgateway (RG) units, etc., at least in part due to the differences in theunderlying access network technologies. For purposes of the presentdisclosure, the end nodes 106 may also be generally referred to as“ports,” which may be monitored or queried by associated access nodeelement 108 using appropriate OAM messaging in one or more “native”protocols. Depending on the access network technology, for example, thenative protocols compatible with the end nodes 106 and the access node108 may be operable with EFM OAM messaging, ATM OAM messaging, and thelike.

An interworking function (IWF) entity 110 is advantageously provided inassociation with the access node 108, either integrated therewith orotherwise, for effectuating Ethernet CFM functionality with respect toone or more of the end nodes 106. Essentially, IWF 110 is operable as anOAM proxy that defines a MEP node within an Ethernet CFM domainincluding other MEP entities such as BRAS 114, whereby an in-bandmaintenance channel may be effectuated between a management node, e.g.,BRAS 114 and an access node and associated IWF. In general, BRAS 114 maybe operable responsive to a BRAS management action such as a request 120by AAA server 118 for initiating a CFM port test/query with respect tomonitoring a particular end node (e.g., loopback). In operation, IWF 110provides bi-directional protocol interpretation capability such thatwhen a management node issues an Ethernet CFM frame pursuant to a porttest query, a logic structure 122 of the IWF entity 110 is adapted tointerpret the Ethernet CFM frame that includes an appropriate querymessage with respect to a particular end node identified within theframe. The particular end node may comprise a physical port or a logicalport, e.g., associated with a permanent virtual circuit or connection(PVC). Another logic structure 124 is adapted to a construct acorresponding query message in a native protocol compatible with theidentified end node. Where the IWF entity 110 is configured as a MEPnode within an Ethernet CFM domain defined on a VLAN, the IWF entity 110includes appropriate logic to resolve port addressing whether a 1:1 portaddressing scheme or an N:1 port addressing scheme is utilized by theVLAN. Associated logic structure 126 is operable to interpret a replymessage provided by the end node responsive to the corresponding querymessage in native protocol. Another logic structure 128 is adapted toconstruct a reply Ethernet CFM frame including a response thatcorresponds to the reply message received from the end node, which replyEthernet CFM frame is transported back to the management node, i.e.,BRAS 114, that initiated the port test/query loopback.

As alluded to hereinabove, the IWF entity 110 may be integrated withinthe access node 108, wherein the various logic structures adapted toeffectuate the functionality set forth above may be combined in anycombination, in software, firmware, program code, etc. Regardless of theexact implementation, those skilled in the art should recognize that theprovisioning of the IWF entity 110 in association with the access node108 supports a distinct maintenance channel that follows the data path,wherein a craftsperson can initiate port loopback monitoring at arelevant point of access, e.g., BRAS 114. In order to ensure seamlessinteroperability between Ethernet CFM with existing access network OAM(such as, e.g., ATM OAM, EFM OAM, etc.), the functionality of IWF 110may be implemented within a number of constraints. For example, the IWFlogic may be required to be compatible with current as well as futureDSL modem technologies. Also, where Ethernet CFM domains involving theaccess network are defined over a VLAN, the IWF logic may need tosupport multiple VLAN address assignment schemes (i.e., 1:1 and N:1VLANs). In addition, the IWF functionality should preferably be operablewith both bridged and routed encapsulation (i.e., tunneling) on theaccess line path in consideration. Exemplary bridged encapsulationimplementations may include Internet Protocol (IP)/Point-to-PointProtocol over Ethernet (PPPoE)/Eth/ATM/DSL as well as IP/Eth/ATM/DSL.Representative embodiments of routed encapsulation include, e.g.,IP/PPP/ATM/DSL and IP/ATM/DSL.

FIG. 2 depicts an exemplary port monitoring scheme 200 according to oneembodiment operable with the network arrangement 100 described abovewith reference to FIG. 1. A policy administration node, e.g., AAA servernode 118, disposed in a regional metro Ethernet is operable to initiatea port test/monitor query message towards a BRAS in the access networkassociated therewith (block 202). Responsive thereto, BRAS generates anappropriate Ethernet CFM frame which includes the query towards aparticular AN/IWF entity in the access network (block 204). The IWFlogic associated with the AN node interprets the CFM message andconstructs an appropriate test/query message (e.g., port status) in anative protocol directed to the port or end node identified in the CFMframe (block 206). Upon receiving the query message in native protocol,the end node generates a response (e.g., port alive, port not alive, noresponse, error response, garbage reply, etc.) and transmits the same tothe AN node (block 208), either in the same native protocol or in adifferent native protocol. Thereafter, the IWF entity associated withthe AN node interprets the test/query response from the end port andconstructs an appropriate Ethernet CFM frame directed towards BRAS(block 210). Responsive to the reply CFM frame from the AN node, BRASgenerates a port test response and forwards it to the policy server(block 212).

In order to support an Ethernet CFM maintenance channel via appropriateIWF functionality in the access network, a new Ethernet CFM frame isintroduced wherein a suitable OpCode field defines the type of portquery/test message (e.g., port loopback) and the payload carries thecontents relating to query messages and reply responses. In onedirection, the Ethernet CFM frame is intended for the AN/IWF entity thatservices the particular end node identified in the payload. By way ofexample, the payload may implement a Type/Length/Value (TLV) encoding tospecify the end node (e.g., DSL port/shelf/VPI/VCI identifier), amongother parameters as will be described below. Alternatively, the payloadcould use a Link Access Procedure on the D Channel (LAPD) mechanism thatcreates a bitstream with respect to a particular target. Regardless ofthe implementation, it should be realized that the semantics of the porttest/query and reply response may preferably be contained within thepayload using suitable TLV encoding.

FIGS. 3A and 3B depict exemplary Ethernet CFM frames operable foreffectuating port testing according to one embodiment of the presentinvention. Reference numeral 300A refers to an Ethernet CFM framegenerated by a BRAS entity with respect to a particular end nodespecified in a Circuit ID field 302. An OpCode field 304 indicates thetype of port test message. An EtherType field 306 identifies the frameas a CFM frame. Depending on the addressing scheme, both S-VLAN ID field308 as well as EtherType VLAN field 310 may be provided. A SourceAddress (SA) field 312 identifies the BRAS's MAC address and aDestination Address (DA) field 314 identifies the AN/IWF entity's MACaddress.

A reply Ethernet CFM frame 300B includes similar fields, e.g., EtherTypeVLAN 330, S-VLAN ID field 328 and EtherType OAM/CFM field 326. In thiscase, however, DA field 334 identifies the BRAS and SA field 332identifies the AN/IWF entity that has received a reply message from theend node responsive to the test/query message from the BRAS. An OpCodefield 324 indicates the type of port test reply message. The results ofthe port testing are included in a Circuit Status field 322 whichprovides a suitable TLV encoding therefor. For example, it may indicate“G.992.1 up”, “1.610 LB down”, or “802.3ah Loopback up”, and the like.Additionally, although not particularly shown, more detailed information(e.g., “802.1ag MEP Address”) may also be provided in the reply EthernetCFM frame 300B via optional TLVs.

It should be recognized that although the frame embodiments 300A and300B appear to depict the respective OpCode fields 304 and 324 on thesame level as the corresponding Ethertype fields 306 and 326, the OpCodefields are in fact on a different level in the sense that these OpCodefields are used to introduce an additional communication channel betweenthe BRAS and DSLAM points, wherein the PDU contents (i.e., the OAMpayload) define one or more messages, such as the port test messages orport test reply messages described above. When a TLV encoding scheme isemployed, the TLV-TYPE field is operable to carry the port test messageor port test reply message code, the TLV-LENGTH field is operable tocarry the length of the TLV, and the TLV-VARIABLE field is operable tocarry the end node or Circuit ID 302 in a suitable format, e.g., DSLport/shelf/VPI/VCI identifier, or C-VLAN ID, or other format.

Regardless of the VLAN port addressing scheme, the AN/IWF entity isoperable to map the port identifier used by the BRAS to a uniquephysical/logical entity (i.e., end node) on the subscriber side. In a1:1 VLAN port addressing scheme, each end user is uniquely identified bya {C-VLAN ID; S-VLAN ID}-tuple that maps to a particular port. WhereasS-VLAN ID 308 is provided as part the Ethernet CFM frame header, theC-VLAN ID may be encoded as Circuit ID TLV 302 as described above. InN:1 VLAN port addressing, the end ports are not uniquely identified by{C-VLAN ID; S-VLAN ID}-tuples since there is no C-VLAN ID per user.Rather, the end ports are differentiated via Circuit ID only.Accordingly, in the 1:1 scheme, the TLV-VARIABLE may carry a C-VLAN IDas a Circuit or end node identifier; whereas in the N:1 VLAN addressingscheme, the DSL port/shelf/VPI/VCI identifier could be used asidentifier of the circuit/end node. The BRAS may therefore provideadditional addressing information within the port test message payload,e.g., by using a Circuit ID TLV encoding similar to the DSL portidentification techniques specified for Dynamic Host Control Protocol(DHCP) and PPPoE.

Based on the foregoing Detailed Description, it should be appreciatedthat the representative embodiments of the present patent disclosureadvantageously provide an effective scheme for extending Ethernet CFMcapabilities to the end nodes in an access network. For example,connectivity testing and monitoring may be implemented from a centralaccess point (e.g., BRAS) that is independent of any existingout-of-band element management system (EMS) deployed for testing DSLAMnodes in the access network. Further, the CFM procedures for end nodemonitoring as provided in accordance with the teachings herein maypreferably implemented independent of the access link technologies.Those skilled in the art should recognize that the embodiments set forthherein can be practiced in an implementation involving software,hardware, or firmware, or any combinations thereof, associated withappropriate network equipment.

Although the invention has been described with reference to certainexemplary embodiments, it is to be understood that the forms of theinvention shown and described are to be treated as exemplary embodimentsonly. Accordingly, various changes, substitutions and modifications canbe realized without departing from the spirit and scope of the inventionas defined by the appended claims.

1. A monitoring method operable with an access network for monitoringend nodes using Ethernet Connectivity Fault Management (CFM)functionality, wherein said access network includes at least one accessnode connected to one or more end nodes and a broadband access server(BRAS) connected to an Authentication, Authorization and Accounting(AAA) server in a regional Ethernet 802.1ag-compliant network,comprising: responsive to an action from the AAA server in the regionalEthernet network, generating by said BRAS an Ethernet CFM frame directedto an access node, wherein said Ethernet CFM frame includes a field thatdefines a type of query message and a payload that includes anidentification of a particular end node served by said access node;interpreting said Ethernet CFM frame by an interworking function (IWF)entity associated with said access node and constructing a correspondingquery message in a native protocol compatible with respect to saidparticular end node; responsive to said corresponding query message fromsaid access node, generating by said particular end node a reply messagein said native protocol directed to said access node; interpreting saidreply message by said IWF entity and constructing a reply Ethernet CFMframe including a response that corresponds to said reply message; andtransmitting said reply Ethernet CFM frame to said BRAS; and responsiveto the reply Ethernet CFM frame, generating a response by the BRAS tothe action from the AAA server and transmitting the response to the AAAserver.
 2. The monitoring method operable with an access network asrecited in claim 1, wherein said IWF entity associated with said accessnode is defined as a Maintenance End Point (MEP) that is part of anEthernet CFM domain including said BRAS.
 3. The monitoring methodoperable with an access network as recited in claim 1, wherein saidEthernet CFM frame is generated by said BRAS responsive to a port querymessage from the AAA server operably coupled to said access network. 4.The monitoring method operable with an access network as recited inclaim 1, wherein said native protocol is operable with Ethernet in FirstMile (EFM) Operations, Administration and Management (OAM) messaging. 5.The monitoring method operable with an access network as recited inclaim 1, wherein said native protocol is operable with AsynchronousTransfer Mode (ATM) Operations, Administration and Management (OAM)messaging.
 6. The monitoring method operable with an access network asrecited in claim 1, wherein said IWF entity associated with said accessnode comprises a Maintenance End Point (MEP) that is part of an EthernetCFM domain defined on a Virtual Local Area Network (VLAN).
 7. Themonitoring method operable with an access network as recited in claim 6,wherein said VLAN is operable with a 1:1 port addressing scheme.
 8. Themonitoring method operable with an access network as recited in claim 6,wherein said VLAN is operable with an N:1 port addressing scheme.
 9. AEthernet Connectivity Fault Management (CFM) monitoring systemassociated with an access network, wherein said access network includesat least one access node connected to one or more end nodes and abroadband access server (BRAS) connected to an Authentication,Authorization and Accounting (AAA) server in a regional Ethernetnetwork, comprising: means associated with said BRAS for generating anEthernet Connectivity Fault Management (CFM) frame responsive to anaction from the AAA server in the regional Ethernet network directed toan access node, wherein said Ethernet CFM frame includes a query messagewith respect to a particular end node served by said access node;interworking function (IWF) means associated with said access node forinterpreting said Ethernet CFM frame and constructing a correspondingquery message in a native protocol compatible with respect to saidparticular end node; and means associated with said particular end node,operable responsive to said corresponding query message from said accessnode, for generating a reply message in said native protocol directed tosaid access node, wherein said IWF means operates to interpret saidreply message in said native protocol and constructs a reply EthernetCFM frame including a response that corresponds to said reply message,said reply Ethernet CFM frame for transmission to said BRAS; and whereinthe BRAS generates a message to the AAA server responsive to the replyEthernet CFM frame.
 10. The monitoring system associated with an accessnetwork as recited in claim 9, wherein said means for generating saidEthernet CFM frame is operable responsive to a port query message fromthe AAA server operably coupled to said access network.
 11. Themonitoring system associated with an access network as recited in claim9, wherein said native protocol is operable with Ethernet in First Mile(EFM) Operations, Administration and Management (OAM) messaging.
 12. Themonitoring system associated with an access network as recited in claim9, wherein said native protocol is operable with Asynchronous TransferMode (ATM) Operations, Administration and Management (OAM) messaging.13. The monitoring system associated with an access network as recitedin claim 9, wherein said IWF means associated with said access nodecomprises a Maintenance End Point (MEP) that is part of an Ethernet CFMdomain defined on a Virtual Local Area Network (VLAN).
 14. Themonitoring system associated with an access network as recited in claim13, wherein said VLAN is operable with a 1:1 port addressing scheme. 15.The monitoring system associated with an access network as recited inclaim 13, wherein said VLAN is operable with an N:1 port addressingscheme.
 16. The monitoring system associated with an access network asrecited in claim 9, wherein said particular end node comprises a DigitalSubscriber Line (DSL) modem port.
 17. The monitoring system associatedwith an access network as recited in claim 9, wherein said particularend node comprises a residential gateway (RG) port.
 18. The monitoringsystem associated with an access network as recited in claim 9, whereinsaid particular end node comprises a network termination (NT) port.